This application claims the priority of German patent document 10 2005 052 929.1-22, filed Nov. 3, 2005, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to an integratable sensor for airfoils of aircraft such as airplanes and helicopters, a rotor blade, and an airplane wing.
Sensors are increasingly integrated in wings of airplanes and in rotor blades of helicopters to measure environmental parameters, such as pressure, temperature, flow, etc. Sensors of this type are subjected to especially rough environmental conditions in operation. For example, the sensors may be damaged by incident particles or contaminants, such as dust and insects.
Especially during use in airfoils and/or rotor blades, the sensors are also subjected to extreme weather influences, such as frost, varying temperatures, and varying air pressure.
In the event of contamination or a defect of the sensors, they must be replaced, which requires great effort and correspondingly high maintenance costs of the airplane or helicopter.
One object of the present invention is to reduce the maintenance costs of helicopters and airplanes equipped with sensors.
Another object of the invention is to provide an integratable sensor which may be put into service more easily and rapidly.
These and other objects and advantages are achieved by the integratable sensor for airfoils of aircraft and helicopters according to the present invention, which comprises a sensor capsule with a measuring element situated therein for measuring an environmental parameter. A capsule carrier, which is integratable in an airfoil of an aircraft, is equipped to accommodate and removably attach the sensor capsule; and contact elements are provided for electrically connecting the sensor capsule to the capsule carrier.
According to the present invention, in the event of a sensor defect or contamination, the defective part of the sensor may be replaced easily, without having to remove the entire sensor from the airfoil or the rotor blade. That is, replaceable sensor capsules may be used, which may be exchanged easily in the event of a defect. Electrical connections, cables, etc. do not have to be dismounted and subsequently mounted again; rather they may remain in location. The removal of the rotor blade and integration of a new rotor blade including the required cabling is no longer necessary in the event of a defective sensor, for example. By integrating the measuring element in the sensor capsule and accommodating the latter in the capsule carrier, an especially reliable and robust sensor having an increased service life also results. The maintenance costs of helicopters and airplanes are significantly reduced.
The contact elements are preferably elastic, providing an especially reliable electrical connection between sensor capsule and capsule carrier, which may be produced easily and disconnected again rapidly. There is no danger that the contacts will break or be damaged by penetrating water, as would be the case with contact pins, for example.
The measuring element is advantageously a pressure sensor element, and the integratable sensor may thus be a pressure sensor. However, it is also possible to use other measuring elements, such as for measuring flow, temperature, humidity, acceleration, or other physical parameters.
The capsule carrier is advantageously integrated permanently in a rotor blade or an aircraft airfoil.
The inner chamber of the sensor capsule is preferably enclosed by a capsule wall, whose external shape is tailored to the interior of the capsule carrier. The measuring element is thus protected in the inner chamber of the sensor capsule; in addition, the sensor capsule may be accommodated completely in the capsule carrier and held securely there.
The sensor capsule is preferably provided with a protective cover, which has at least one through opening as an air passage. In this manner, especially good protection of the measuring element in the inner chamber of the sensor capsule results, while the ambient air nonetheless is able to reach the measuring element in the inner chamber.
The surface of the protective cover of the sensor capsule advantageously runs in a plane with the surface of the airfoil in the integrated state. The flow on the airfoil thus remains largely uninfluenced by the sensor.
The continuous opening in the protective cover advantageously runs at least partially diagonally or transversely to the surface of the protective cover. Direct impact of particles on the measuring element in the inner chamber of the sensor capsule is prevented by the structuring of the protective cover because of the geometry of the through openings.
In particular, the sensor element may comprise at least two wafers which are bonded to one another, and are shaped in such a way that they form a cavity sealed by a diaphragm. An especially reliable pressure sensor is thus provided, which is producible cost-effectively and provides precise measurement results. In addition, it has a very long service life.
The sensor capsule is preferably held in the capsule carrier by a magnetic force, which results in a still further reduction of the effort when mounting and/or replacing the sensor capsule. The sensor capsule is nonetheless held securely by the magnetic force in the capsule carrier, so that it withstands high accelerations. The magnetic force is generated, for example, by a permanent magnet or by electromagnets in the capsule carrier, for example. An electromagnet has the special advantage that it exerts an even stronger force for retaining the sensor capsule and may be turned off to replace the sensor capsule. In contrast, a permanent magnet has the advantage of simpler and/or less costly construction of the sensor.
The permanent magnet may, for example, be situated in the capsule carrier, while ferromagnetic metal such as iron is situated in the sensor capsule. Alternatively, it is also possible to situate the permanent magnet in the capsule and ferromagnetic metal in the capsule carrier. The latter arrangement has the advantage that, when the capsule carrier is laminated into the carbon-fiber reinforced plastic material of the rotor blade or the airfoil, damage to the permanent magnet because of the heat developed and possibly exceeding the Curie temperature of the permanent magnet are avoided. Furthermore, it is also possible to situate a permanent magnet in both the sensor capsule and the capsule carrier.
The capsule carrier preferably has planar electrical contacts for contacting the elastic contact elements of the sensor capsule, which achieves a very secure and reliable electrical connection between capsule carrier and sensor capsule, due to the planar surface of the capsule carrier, which is easily disconnectable and is protected against damage such as buckling, breaking, or due to penetration of water.
The capsule carrier advantageously has a wall whose interior is tailored to the external form of the sensor capsule. Thus, for example, a formfitting integration of the sensor capsule into the capsule carrier may be performed. In addition, the sensor capsule is secured against strong radial forces, such as occur in the rotating rotor blade, for example, by the guide in the capsule carrier.
The capsule carrier and the sensor capsule are preferably mutually engaged using a notch and a corresponding projection, in order to prevent relative twisting. In this manner, the sensor capsule can be introduced in a defined way into the capsule carrier, so that the contact elements of the sensor capsule each rest precisely on the planar contacts of the capsule carrier. Mutual twisting of sensor capsule and capsule carrier is prevented by the notch and the corresponding projection.
The sensor element advantageously comprises a cavity which is hermetically sealed by a flexible diaphragm, and the interior of the cavity diametrically opposite the diaphragm is tailored to the contour of the diaphragm in the deflected state. The diaphragm is protected better from damage in this manner, since the diaphragm itself rests flat on the contoured interior of the cavity in the event of inhomogeneous eccentric load. Moreover, an overload protection at excessive pressure results, due to the delimitation of the deflection of the diaphragm, by which tearing of the diaphragm is prevented.
According to one aspect of the present invention, a rotor blade for helicopters is provided, in which a sensor according to the present invention is integrated.
According to a further aspect of the present invention, an airplane airfoil is provided, in which a sensor according to the present invention is integrated.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.